AbstractJoint analysis of multichannel seismic reflection profiles calibrated with well-logs across the northern part of the Lampedusa Plateau (central sector of the Pelagian Block, Sicily Channel), of structural data collected on Lampedusa island, and of GNSS geodetic velocities of sites on the islands and on the northern shore of the Channel, suggests that this part of the plateau forms an anticlinorium (Lampedusa Plateau Anticlinorium, LPA). The LPA developed during Paleogene to Early Miocene intraplate contraction followed by Miocene to current strike-slip deformation. It is formed by WNW-ESE striking highs and lows, which have an ~20 km average wavelength and culminate at the Lampione-Lampedusa High. These broad folds are bounded by high-angle faults with a reverse component of displacement, which cut Eocene to Lower Pliocene strata offshore, and Late Miocene strata on Lampedusa. Extensional faults, that have a bathymetric expression and are responsible for marked stratal tilting due to their listric geometry, are only found to the NE of the island and are associated to the rifting that affected the central part of the Sicily Channel in the Pliocene-Quaternary. Seismic reflection profiles show that normal fault activity peaked during the middle part of the Pliocene and strongly diminished afterward. Appraisal of recent plate motion reconstructions and of published and new structural data offshore and on-land suggest that the main growth phase of the LPA occurred during (Late Cretaceous?) Paleocene-Early Miocene ~N-S convergence between Nubia and Eurasia and associated intraplate shortening. Starting from Early Miocene, likely in response to a CCW rotation of the plate convergence direction, strike-slip deformation occurred with a ~NW-SE shortening axis and ~NE-SW extension axis. During this time span the previous contractional structures were locally reactivated in transpression. The two different strain regimes, extensional and transpressional that established since Miocene NE and W to NW of Lampedusa, respectively, still persist today as documented by geodetic velocities.

AbstractFramed in the current geodynamics of the central Mediterranean, the Aeolian-Tindari-Letojanni fault system is part of a wider NW-SE oriented right-lateral wrench zone which accommodates diverging motion between regional-scale blocks located at the southern edge of the Calabrian Arc. In order to investigate the structural architecture and the active deformation pattern of the northern sector of this tectonic feature, structural observations on-land, high and very-high resolution seismic reflection profiles, swath bathymetry and seismological and geodetic data were merged from the Lipari-Vulcano volcanic complex (central sector of the Aeolian Islands) to the Peloritani Mountains across the Gulf of Patti. Our interpretation shows that the active deformation pattern of the study area is currently expressed by NW-SE trending, right-transtensional én-echelon fault segments whose overlapping gives rise to releasing stepover and pull-apart structures. This structural architecture has favored magma and fluid ascent and the shaping of the Lipari-Vulcano volcanic complex. Similarly, the Gulf of Patti is interpreted as an extensional relay zone between two overlapping, right-lateral NW-SE trending master faults. The structural configuration we reconstruct is also supported by seismological and geodetic data which are consistent with kinematics of the mapped faults. Notably, most of the low-magnitude instrumental seismicity occurs within the relay zones, whilst the largest historical earthquakes (1786, Mw=6.2; 1978, Mw=6.1) are located along the major fault segments.

AbstractLate Holocene (~6.5 ka) shorelines represented by tidal notches, beach deposits, wave-cut terraces and intertidal organic rims are raised from few decimetres up to 5.5 m above the present sea level in the southern part of the Calabrian Arc, southern Italy. At five localities (Capo Vaticano and Scilla in southern Calabria and Taormina, Schisò, Capo Milazzo in north-eastern Sicily), the uplifted paleo-shorelines form a distinct vertical sequence where the older shorelines rest invariably above the younger ones. Such arrangement documents the occurrence of abrupt uplift events that, within the limits imposed by existing age controls, we attribute to ancient earthquakes. A comprehensive appraisal of published studies has allowed to draw an inventory with a total of possibly sixteen earthquakes which, based on the amount of shoreline displacement (~0.5-2 m) and the length of coastal section involved in uplift, were likely to be of strong size. It appears that the amount of uplift decreased with time during the Late Holocene at all sites but Capo Vaticano, where it remained almost stationary. The co-seismic events appear grouped within four temporal clusters, during which uplift occurred at most of the five coastal sectors investigated here. These clusters spanned time intervals whose duration, although difficult to bracket with precision, is of few hundred years, and are separated by longer (~0.5-1.5 ka) periods of apparent tectonic quiescence. The sources of co-seismic uplifts are still undefined, and should be searched between normal faults in the stretched Calabrian upper crust, or lower crustal thrust faults related to the Ionian subduction.